Question

lab report discussion/conclusion of Chemiluminescence Optimization of a Chemical Reaction

Answer 1

Luminescence is the most conveniently defined as the radiation emitted by a molecule, or an atom, when these species return to the ground state from the exited state. chemiluminescence reaction yields one of the reaction products in an electronic excited state producing light on falling to the ground state.Chemiluminescence happens when reactants A and B mix to emit light and some heat. The reason there is an emission of light is because there is an intermediate that is in its excited state. One great example of a chemiluminescenet is Luminol. Luminol is a chemical that will glow blue when it goes under the reaction. The reaction must contain n appropriate oxidizing agent. Luminol will not dissolve in water but will dissolve in most organic solvents. Luminol is as very important chemical that is used by crime scene investigators. They use this chemical to find out if there are traces of blood anywhere on the scene and this will help them because once they find blood, then they can analyze it and maybe get a suspect. As luminol is put on the blood, it reacts with the hemoglobin, more specifically the iron. Another thing luminol is used for is the detection of iron, copper, and cyanides in cellular assays by biologists.

n general, a chemiluminescent reaction can be generated by two basic mechanisms (Figure 2) in a direct reaction, two reagents, usually a substrate and an oxidant in the presence of some cofactors, react to from a product or intermediate, sometimes in the presence of a catalyst. Then some fraction of the product or intermediate will be formed in an electronically excited state, which can subsequently relax to the ground state with emission of a photon. The substrate is the CL, precursors, which is converted into the electronically excited molecule, responsible for light emission or acting as the energy as transfer donor in indirect CL. The catalyst enzyme or metal ions reduce the activation energy and provide an adequate environment for producing high CL efficiency out of the process

Some Factors Influencing Chemiluminescence’s Emission

Because of the cited dependence of CL intensity upon various parameter, CL measurement’s are strongly modified by experimental factors that affect quantum yield and rate of reaction, such as

(i) the chemical structure of the CL precursor, not only the central portion containing the electronically excited group, but also the side chain;

(ii) the nature and concentration of other substrates affecting the CL pathway and favoring other nonradiative competition process;

(iii) the hydrophobicity of the solvent and solution composition as example the of luminal oxidized in dimethylusfoxide (DMSO) is 0.05 compared with 0.01 in water, the colors being blue-violet (425nm) and blue green (480-502nm), respectively;

(iv) the presence of energy transfer acceptors